Sure, we have AmigaOS and MorphOS, but those cost money and require special hardware. For those of us more interested in running an Amiga-like operating system on regular, x86 hardware, there's AROS. Two AROS distributions, Icaros Desktop and AspireOS both saw new releases recently.

"Ancient" basically just denotes time... AROS is, to be sure, by far the most sane of those (directly) AmigaOS-influenced efforts, but that influence is fairly ancient, as far as timeline of home computing goes.

And yeah, about that "kept on developing" ...still no memory protection (hence also, sort of, no proper multitasking, just the not-quite-one that depends on well-behaving apps, where any program can essentially take over).
A decade more till it comes? Two decades? Will by then all of ~Amiga application development be just porting OSS stuff from the ~PC?